The reason? Ryan is reportedly busy with a handful of other projects, including the upcoming series 'Terriers' and 'Ridealong,' set to air on FX and FOX, respectively.

Ryan, who created 'The Shield' in 2002, has been in charge of 'Lie to Me' since the beginning of season 2.

Ryan's exit may be a telling sign for the sophomore series, which is set to return on Jun. 7. The ratings-challenged series, starring Oscar nominee Tim Roth, is said to be on the bubble as May upfronts approach.

'Terriers,' starring Donal Logue, is an hourlong comedy, about an ex-cop who partners with his best friend, played by Michael Raymond James. 'Ridealong' follows three groups of police officers in Chicago.